Vendor code using godep.

For 3rd parties building binary packages, and for build consistency in
general, it is very helpful to have the same set of dependencies at
any time the product is built.

See [tools/godep](https://github.com/tools/godep) for further details.

vendor/golang.org/x/sys/unix/mksysnum_freebsd.pl

@@ -0,0 +1,50 @@
+#!/usr/bin/env perl
+# Copyright 2009 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+#
+# Generate system call table for FreeBSD from master list
+# (for example, /usr/src/sys/kern/syscalls.master).
+
+use strict;
+
+if($ENV{'GOARCH'} eq "" || $ENV{'GOOS'} eq "") {
+	print STDERR "GOARCH or GOOS not defined in environment\n";
+	exit 1;
+}
+
+my $command = "mksysnum_freebsd.pl " . join(' ', @ARGV);
+
+print <<EOF;
+// $command
+// Code generated by the command above; see README.md. DO NOT EDIT.
+
+// +build $ENV{'GOARCH'},$ENV{'GOOS'}
+
+package unix
+
+const (
+EOF
+
+while(<>){
+	if(/^([0-9]+)\s+\S+\s+STD\s+({ \S+\s+(\w+).*)$/){
+		my $num = $1;
+		my $proto = $2;
+		my $name = "SYS_$3";
+		$name =~ y/a-z/A-Z/;
+
+		# There are multiple entries for enosys and nosys, so comment them out.
+		if($name =~ /^SYS_E?NOSYS$/){
+			$name = "// $name";
+		}
+		if($name eq 'SYS_SYS_EXIT'){
+			$name = 'SYS_EXIT';
+		}
+
+		print "	$name = $num;  // $proto\n";
+	}
+}
+
+print <<EOF;
+)
+EOF